Documentation/admin-guide/thunderbolt.rst

1 .. SPDX-License-Identifier: GPL-2.0
25 -----------------------------------
27 should be a userspace tool that handles all the low-level details, keeps
31 found in ``Documentation/ABI/testing/sysfs-bus-thunderbolt``.
35 ``/etc/udev/rules.d/99-local.rules``::
50 Some USB4 systems have a BIOS setting to disable PCIe tunneling. This is
69     a challenge that should match the expected one based on a random key
70     written to the ``key`` sysfs attribute. In BIOS settings this is
71     typically called *One time saved key*.
102 -----------------------------------------------------------------
105   /sys/bus/thunderbolt/devices/0-1/authorized	- 0
106   /sys/bus/thunderbolt/devices/0-1/device	- 0x8004
107   /sys/bus/thunderbolt/devices/0-1/device_name	- Thunderbolt to FireWire Adapter
108   /sys/bus/thunderbolt/devices/0-1/vendor	- 0x1
109   /sys/bus/thunderbolt/devices/0-1/vendor_name	- Apple, Inc.
110   /sys/bus/thunderbolt/devices/0-1/unique_id	- e0376f00-0300-0100-ffff-ffffffffffff
115   # echo 1 > /sys/bus/thunderbolt/devices/0-1/authorized
120 set to ``secure``, it has an additional attribute ``key`` which can hold
121 a random 32-byte value used for authorization and challenging the device in
124   /sys/bus/thunderbolt/devices/0-3/authorized	- 0
125   /sys/bus/thunderbolt/devices/0-3/device	- 0x305
126   /sys/bus/thunderbolt/devices/0-3/device_name	- AKiTiO Thunder3 PCIe Box
127   /sys/bus/thunderbolt/devices/0-3/key		-
128   /sys/bus/thunderbolt/devices/0-3/vendor	- 0x41
129   /sys/bus/thunderbolt/devices/0-3/vendor_name	- inXtron
130   /sys/bus/thunderbolt/devices/0-3/unique_id	- dc010000-0000-8508-a22d-32ca6421cb16
132 Notice the key is empty by default.
139 plugged a key needs to be created and sent to the device::
141   # key=$(openssl rand -hex 32)
142   # echo $key > /sys/bus/thunderbolt/devices/0-3/key
143   # echo 1 > /sys/bus/thunderbolt/devices/0-3/authorized
146 the key is stored on the device NVM.
149 device using the same key::
151   # echo $key > /sys/bus/thunderbolt/devices/0-3/key
152   # echo 2 > /sys/bus/thunderbolt/devices/0-3/authorized
155 on the key, the device is connected and the PCIe tunnels are created.
160 the device without a key or write a new key and write 1 to the
161 ``authorized`` file to get the new key stored on the device NVM.
163 De-authorizing devices
164 ----------------------
165 It is possible to de-authorize devices by writing ``0`` to their
171 When a device is de-authorized the PCIe tunnel from the parent device
173 down. This is essentially the same thing as PCIe hot-remove and the PCIe
180 ------------------------------
200 ----------------------------------------------------
221 device - then you need to connect that particular device).
223 Note an OEM-specific method to power the controller up ("force power") may
227 After that we can write the firmware to the non-active parts of the NVM
231   # dd if=KYK_TBT_FW_0018.bin of=/sys/bus/thunderbolt/devices/0-0/nvm_non_active0/nvmem
236   # echo 1 > /sys/bus/thunderbolt/devices/0-0/nvm_authenticate
239 it comes back the driver notices it and initiates a full power cycle.
246   # cat /sys/bus/thunderbolt/devices/0-0/nvm_authenticate
248   # cat /sys/bus/thunderbolt/devices/0-0/nvm_version
259 Upgrading on-board retimer NVM when there is no cable connected
260 ---------------------------------------------------------------
267   # echo 1 > /sys/bus/thunderbolt/devices/0-0/usb4_port1/offline
273   # echo 1 > /sys/bus/thunderbolt/devices/0-0/usb4_port1/rescan
275 This enumerates and adds the on-board retimers. Now retimer NVM can be
281   # echo 1 > /sys/bus/thunderbolt/devices/0-0/usb4_port1/rescan
286   # echo 0 > /sys/bus/thunderbolt/devices/0-0/usb4_port1/offline
289 --------------------------------------------------
300 ---------------------------------
309 ``thunderbolt-net`` driver is loaded automatically. If the other host is
310 also Linux you should load ``thunderbolt-net`` manually on one host (it
313   # modprobe thunderbolt-net
316 is built-in to the kernel image, there is no need to do anything.
323 Forcing power
324 -------------
325 Many OEMs include a method that can be used to force the power of a
330 For example the intel-wmi-thunderbolt driver exposes this attribute in:
331   /sys/bus/wmi/devices/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power
333   To force the power to on, write 1 to this attribute file.
334   To disable force power, write 0 to this attribute file.
336 Note: it's currently not possible to query the force power state of a platform.